Planer-head.



H. J. MITCHELL.

PLANER HEAD. APPLICATION FILED DBO. a, 190'9.

995,024, Patented-June 13, 1911.7

UNITED' STATES OFFICE.

HARRISON J. lVIITCI-IELL, OF BELOIT, WISCONSIN, lASSLIGrNOR TO THE BERLIN MACHINE WORKS, OF BELOIT, WISCONSIN, A CORPORATION 0F WISCONSIN.

PLANER-HEAD.

Specification of Letters Patent.

Patented June 13, 1911.

Application led December 8, 1908. Serial No. 466,491.

To all whom it may concern: 4

Be it known that I, HARRISON J. MITCHELL, a citizen of the United States, residing at Beloit, in the county of Rock and State of Wisconsin, have invented certain newl and useful Improvements in Planer-Heads, of which' the following is a specification.

My invention relates to improvements 1n the heads or cylinders of planing machines, and concerns more particularly improved means for liXedly securing and holding the planer knives in place. My improved securing and knife locking devices not only eli'ectively and efficient-ly maintain the knives in operative cuttingV position, but they are eX- tremely simple in construction and are especially economical as regards their manufacture. For the straight planer knives of the cylinder or head I provide the periphery or outer surface of the planer cylinder with undercut or dovetail grooves, portions of the knives occupying parts ofV such grooves, while wedge gibs or keys also reside inthe grooves and act as locking or securing means for holding and maintaining the knives in cutting or operative position. In connection with these gibs I use conical ended screws, the conical parts of which are in reality wedges which act on the gibs to force the same into knife holding relation. TheseV gibs are also free to respond to the action of centrifugal force during the rotation of the planer cylinder and act to more firmly bind the knife in place as the speed increases.

In the accompanying drawings, forming a part of this specification, and throughout the various views of which like reference characters refer to the same parts, I Vhave illustrated a desirable embodiment of this invention, and referring to these drawings it will be noted that Figure 1 is a fragmentary end elevation of a planer cylinder, one knife being illustrated and locked or secured in place by my improved means for accomplishing this function and purpose; Fig. 2 is a cross-section through the planer cylinder and shows one of the conical ended screws for forcing the wedge gib into knife holding position; and Fig. 3 is a perspective view of one of theV gibs or locking keys.

yBy reference to the drawings it will be noted that the periphery of the planer cylinder or head 10 is provided with a plurality of longitudinal undercut grooves 11,

only one of which is shown in the drawings, and thatone side 12 of the groove may be substantially radially arranged or disposed if desired, or may be inclined to any suitable degree. Each groove 11 has an inward eX- tension 13 adapted to accommodate and receive the inner portion of a planer knife 14, a part of which resides in the slot or groove 11, while its front cutting edge 15 projects someV distance beyond the outer surface or periphery ofthe cylinder. Also located in this dovetail or undercut groove 11 I employ one or more gibs or keys 16, each having a flat or preferably longitudinallyrecessed surface 17 adapted to bear on the front face of the knife, andA an opposite' surface 1S to co-act with the side 12 of the groove. It should be noted', however, that the angle between thefaces 17 and IS of the gib or locking key is slightly more acute than the angleY between the two sidewalls or faces of th'e groove, whereby as the gib is forced outwardly, by means hereinafter described: or by centrifugal force, it is certain to secure and hold in place the outer or cutting portion of the knife. Each gib or key I6 has a plane bevel surface 19 bearing against which, are the conical or wedge surfaces 20 at the ends of onev or more screws 21 having angular heads 22, t-he threads of the screws co-acting with those of threaded apertures 23 extended transversely to the axis of the cylinder through the wall 24 between the undercut or dovetail groove 11 and any suitable number of outer recesses 25 provided to accommodate the screw heads 22. The threaded holes 23 are desirably first provided in the planer head and then the slots or grooves 11 are milled to substantially the depth of the axis of holes 23leaving below the main portions of the grooves 11 half-round threaded pockets or recesses 23 intended to accommodate and support the inner ends of the screws 21, as the latter are fed inwardly to tighten the glb.

As is clearly indicated in the drawings,

the cylinder just in front of the cutting edges 15 of the knives is recessed at 26 to provide cavities or spaces for the accomodation of the chips removed from the lumber by the knives. By making the gibs or locking keys 16 of hardened steel they perform the additional function of acting as efficient chip breakers.

It should be apparent from a consideration of this construction and the above de-l scription that as the screws 21 are turned, by applying wrenches or the like to their angular heads 22, their conical or wedge ends 20 which bear against the bevel surfaces 19 of the gibs will be forced inwardly toward the knives 14, which results in a substantially-radial outward movement of the wedge gib or key 16 and also a bodily movement thereof toward the knife. It will, therefore, be obvious, that each gib or key has a bearing on its knife, and that the latter is securely and effectively maintained in operative or planing position. Owing to this outward movement of the gib, its outer part becomes securely wedged between the wall 12 of the groove and the face of the knife, and the bodily movement of the gib toward the knife, due to the thrust which it receives at its lower portion by the cone screw or screws, causes an efficient bearing of the gib on the knife in the bottom part of the groove. When the bearing face of the gib is slightly longitudinally recessed, as illustrated, the gib or key is sure to have an effective bearing on the knife at the gibs outer and inner portions, thereby eliminating all possibility of obtaining a bearing or pressure on the knife due to its possible uneven thickness at some intermediate point without obtaining the desired pressure thereon near the cutting edge. CentrifugalV force, of course, has a tendency to throw the knife outwardly out of its socket, but this force also acts similarly on the key or gib, and consequently as this centrifugal force increases, due to the increased speed of rota-- tion of the cylinder, the knife is held in place all the more firmly and securely.

It may be noted that the gibs or keys 16 are in reality double wedges, one of such wedges constituting the outer portion of the gib locking the knife against outward displacement by bearing against the same and against one face of the undercut groove. Obviously then if the knife or gib is acted upon by centrifugal force the latter locks and secures the former all the more tightly in place. If for any reason the knife has a tendency to be driven inwardly, as when it strikes a knot or the like, and tends to carry the gib with it, the latter, by co-action with the wedge of conical ends of the screws, presses all the more firmly against the knife andprevents such inward movement of the same.

As many gibs or locking keys may be employed for each knife as appears necessary or desirable, and although in the drawings I have indicated only one of such keys, it will be apparent that the number may be multiplied or increased, depending, of course, to a considerable extent, upon theV length of knife employed. The number of cone screws used for each gib is quite immaterial and may be made to conform to the length of gib used. It may be noted, however, that in some cases one screw will be suficient for a gib, whereas in other instances it may be desirable or preferable to use more than one for a single key.

To those skilled in this art it will be obvious that the minor mechanical details of the construction herein set forth in reality form no part of the heart and essence of the invention, and that they may be modified within wide limits without departure from the substance of the invention Vor the sacr`- fce of any of its benefits and advantages.

I claim:

1. The combination of a' planer cylinder having an undercut groove on its periphery, a knife in said groove, a gib in said groove adapted to bear against said knife, and provided with a beveled surface and a' screw having a conical point adapted to bear against the beveled surface' of said gib and force the gib toward the contracted part of the groove to lock the knife in place, substantially as described.

2. The combination of a planer cylinder having an undercut groove on its periphery, a knife in said groove, a wedge-shaped gib in said groove adapted to bear against said knife, and a wedge adapted to engage with said wedge-shaped gib to force said gib toward the contracted mouth of said groove to lock the knife in place, substantially as described.

3. The combination of a planer cylinder having an undercut groove on its periphery, a knife in said groove, a wedge gib in said groove adapted to bear against said knife, said gib having a beveled surface, and one or more screws adapted to force said gib toward the contracted part of said groove to lock said knife in place, each of said screws having a conical end bearing against the beveled surface of the gib, substantially as described.

4. The combination of a planer cylinder having an undercut groove on its periphery,

a knife in said groove, a gib in said groove adapted to bear against said knife, and one or more screws arranged transversely to said gib and having conical ends co-a'cting therewith to force the gib toward the contracted part of the groove whereby to lock said knife in place, substantially as described.

5. The combination of a planer cylinder having an undercut groove on its periphery, a knife in said groove, a double wedge gib in said groove adapted to bear Vagainst said knife, and means co-acting with said gib to force onerwedge portion thereof toward the contracted part of said groove to fasten said knife in position against outward displace; ment, the second wedge portion of said gib cooperating with saidV means whereby to increase the binding effect of the gib on the knife upon inward shifting of the gib or knife, substantially as described.

6. The combination of a pianer cylinder having anundercut groove on its periphery, a knife in said groove, a wedge gib in said groove adapted to bear against said knife, and wedge-means co-acting with said gib to force the wedge portion of the latter t0- ward the contracted part of the groove to fasten said knife in position against outward displacement, said gib coperating with said wed e means whereby to increase the binding e ect of the gib on the knife upon inward shifting of the gib or knife, mdwrantnwuw as nqmr'iiwfi.

7. The combination of a planer cylinder having an undercut groove on its periphery, aknife in said groove, a wedge gib in said groove adapted t bear against said knife, and means having a surface inclined to Said knife and cosacting with said gib to force the wedge portion thereof toward the contracted part of said groove to fasten said knife in position against outward displacement, said gib coperating with said inclined surface whereby to increase the binding effect of the gib on the knife upon inward shifting of the gib or knife, substantiaily as described.

HARRISON J. MITCHELL. i/Vitnesses z L. A. Ross` W. E. BERTSCH.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. G. 

